The Kolno Plateau mesoregion represents a distinguished geographic unit situated on the border of lakelands and old morainic uplands. Development of the relief of the area has so far been believed to be related to the frontal deglaciation of the Continental Glacier of the MiddIe Polish Mława stage (R. Galon, L. Roszko, 1967, J. Kondracki, S. Pietkiewicz, 1967, S. Z. Różycki, 1967, 1972). The mesoregion in question is situated within the extensive pre-Quaternary bed uplift whose surface lies at a height of 20 m a.s.l. The relief of the Kolno Plateau is characterized by meridian orientatione of the major land highest points with simultaneous lack of typical parallel frontal-morainic forms with glacial drainages in its forefront. There occur four complexes of elevations exceeding 200 m above sea level, separated by parallel running valleys where the altitudes drop to below 158 m above sea level. To the south, the Jedwabne-Jurzec-Obrytki morainic plateau extends (the highest point of 202.9 m above sea level). A number of fissure and ice contact forms occur on its surface and in its immediate vicinity; the forms are of the keme, dead-ice hill, and glacifluvial-ablation cone types. The next two complexes of rises are formed by the glacifluvial keme hills Dzięgiele-Świdry-Siwki (the highest point 204 m above sea level) and Golanki-Łebki Duże-Łubiane (the highest point 205 m) a.s.l. The northernmost is the Marki-Brzezno-Kownacinek moranic plateau (elevation 206 m a.s.l.) accompanied by kemes, dead ice hills, and a keme terrace. A continuation northwards of the central zone of the heights constitutes the Stawiane-Rakowo glacifluvial keme ridge (elevation 189 m). From the west the Gałązki-Kumels (elevation 213.6 m) marginal ridge joins the Jedwabne-Gałązki highest zone; the ridge is surrounded by numerous fissure forms. An extension of the ridge is the vast melting forms. Lachowo-Świątki Rydzewo-Wszebory plateau (elevation 177.5 m), which dissects a number of radially oriented valleys with fissure forms and ice contact forms. An analysis of the relief permitted a conclusion that in the process of deglaciation in that area of the last glacier cap of the North Masovian (the Wkra G III + 2) stage of the Middle Polish glaciation, the first to emerge from under the tight continental glacier cover were the highest lying fragments of the plateau. The initial stage was a strong fissure formation followed by the formation of melting forms. The reasons for that phenomenon should be sought in the unevenness of the older base and in the physical properties of ice masses (fissure development, mineral material content, etc.). During activity of the melting forms in the ice sheet, a fissure network was formed in their immediate vicinity, where the accompanying forms developed, such as: kemes, keme terraces, dead ice hills, and glacifluvial-ablation cones. Thus highest elevations zone of the Kolno Plateau was therefore formed in the initial stages of the glacier deglaciation and represents a macroform of the glacial relief of an ice sheet type of a meridional orientation (A. B. Basalykas, 1969). It dissects the glacial depressions which used to be the areas of the present Biebrzanska Basin and the Kurpiowska Plain.
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